Engine fuel test device



Oct. 29, 1963 B. L. MICKEL ENGINE FUEL TEST DEVICE 2 Sheets-Shea?I 1Filed April .29, 1960 ESG Oct. 29, 1963 B. L. MICKEL 3,108,468

' ENGINE FUEL TEST DEVICE Filed April 29, 1960 2 Sheets-Sheet 2 Pawn? 5PSUPPLY 6.3/ POWL'? SUPPLY INV EN TOR.

Bla /mrd L. Michel By ATTORNEY United States Patent O 3,103,4i68 ENGINEFUEL TEST DEWCE Blanchard L. Michel, Munster, Ind., assigner to Standard@di Company, Chicago, lli., a corporation of indiana Filed Apr. 29,1950, Ser. No. A25,577 2 Claims. (Ci. 7S-6l) This invention relates to alaboratory iapparatus for testing fuel compositions for Iuse in internalcombustion engines. This invention further relates to an improved enginefuel test device for giving indications of deposit forming 1an-dremoving properties of fuel compositions which indications may be may becorrelated with deposit for-ming and removing properties of the sampleas a fuel in an operating internal combustion engine, particularly withregard to deposit weight and deposit movement in rthe fuel-inductionsystem of an internal combustion engine.

In the development of new fuel compositions `by blending as well as 'byformulating with addition agents, gum and varnish deposition andparticularly deposits on the fuel-induction system of an internalcombustion engine under conditions of operation of the engine are amajor concern. lt is desirable to formulate engine fuel compositions sothat they will function without leaving such deposits and sometimes with.the `additional ability to remove deposits which have already beenformed Within the engine.

In an internal combustion engine, deposits may form from the fuel underaction of heat in the fuel-induction system. The deposits may theneither 'accumulate within the induction system and cause intakevalve-sticking, etc. or they may move through the induction system andinto the combustion chamber without accumulating. Once in the combustionchamber, the deposits may be eliminated through normal combustionprocesses withinthe combustion chamber. Deposit movement, as discussedherein, relates to the movement of deposits through the fuelinductionsystem.

The fuel-induction system is the system 4through which fuel passes inKan internal combustion engine before entering the combustion chamber.For example, in a sparkignition internal combustion engine, thefuel-induction system generally is defined as that series of passagewaysbetween the carburetor throttle plate and the underside or tulip portionof the intake valves. The mixing of fuel and airis `generally justupstream of the throttle plate and the fuel-air mixture passes aroundthe throttle plate before entering the network of passageways which leadto the individual combustion chamber. En route to lche combustionchamber, the fuel-air mixture encounters conditions which may lead tothe formation or separation of harmful fuel deposits. At the throttleplate, in the nearly closed idling position, 'deposits which seriouslyrestrict air-fuel flow may be formed or thrown out of suspension orsolution. Such deposits may lead to rough idling 'and engine stall.

A second point where deposits may form is on surfaces adjacent to the:carburetor-heat porting. Here, hot exhaust gases are diverted from theexhaust manifold into the area around the carburetor base for thepurpose of improving fuel vaporization and reducing carburetor icing;surface temperatures of several hundred degrees may be encountered. Fueldroplets which contact this hot surface are immediately vaporized butthe non-volatile fuel components and impurities may remain behind on thehot surface to be #oxidized or thermally cracked, thereby forminggumlike Ideposits or gum-precursor materials.

While thin varnish ims in the vicinity of the carburetorheat porting maynot be directly harmful, realdiiculties dddd Patented Get. 29, i963 ICCmay occur in yet a third area, that of the intake valves and ports.

The induction-system surfaces upstream of the intake valve may beconsidered to be `a reactor in which heavy ends are generated by dashdistillation and gum and gum precursors are formed or separated from thefuel. This ixture of heavy ends and gum-like materials is thought tomigrate, as a thin liquid hlm, downstream and into the vicinity of theintake valves. Temperatures as high as 600 F. may prevail on the intakevalve surfaces. W'hen the moving film of heavy ends ows onto the hotvalve sunfaces, further oxidation as well las cracking and ooking mayoccur. The formation 'of deposits on valves and port surfaces is thoughtto be further aggravated by the tiashback of hot combustion gases aswell as by certain lube-oil additives and components. If the fuel haslittle deposit-forming tendency, lthen it is unlikely that engine damagewill occur. If the deposits formed are not adherent, but instead, areswept downstream and into the combustion chamber, then again, valvedam-age is unlikely. However, if the fuel tends to form deposits whichare both large in quantity and adherent in nature, then the sticking(and subsequent burning) of valves and reduction in volumetriceiiiciency and performance is very probable.

Any proposed new fuel composition produced in the laboratory must beextensively tested before it may be used as a commercial engine fuel.Laboratory tests, 'although they are helpful and enable the researcherto foresee certain deposit forming tendencies of engine fuel, are`generally not entirely reliable; many of the test procedures do notgive results which are correlated with results under engine operation.After passing the laboratory tests, proposed fuel compositions are thensubjected to expensive and time-consuming engine tests which areactually conducted in an internal combustion engine under operatingconditions. Some such engine tests take up to a week or more to run andbecause yof the limited number of engines available for engine tests, itis desirable to screen out as many proposed fuel compositions aspossible by a laboratory technique or with a laboratory device.Laboratory devices do not give adequate definitions or measurements ofdeposit movement within an engine.

The present invention provides a fuel testing device for testing enginefuels, which device gives results with regard to gum or deposit formingand removing properties of a fuel and particularly with regard to'deposit weight and deposit movement through the induction system of aninternal combustion engine. The results obtained using the presentdevice are correlated with results obtained in the induction system ofan operating internal combustion engine. The `device of this inventionmay be used in a technique for determining deposit movement and weightin a minimum of time and with little fuel expenditure. The device isparticularly useful in screening samples of fuel compositions in alaboratory, thereby eliminating many of the actual engine testsnecessary during development of a fuel.

The device of this invention provides a rotatable heated conduit whichis removable from the heating source and is interchangeable with otherconduits. Means for rotating the con-duit in heatabie proximity to theheating source are also provided. The conduit is positioned at aninclined angle to provide gravityV flow therethrough from an upper endto a lower end. The heating source may be capable of providingpreselected temperatures within the range of from about to about 700 F.or higher. The conduit is provide-d with fuel and air inlet means at theupper end and outlet means at the lower end. As a technique fordetermining deposit forming or removing properties of a fuelcomposition, the

conduit is heated to a preselected temperature and fuel and `air areintroduced at the inlet and iiowed by gravity through the conduit whilerotating the conduit. The deposits formed in or removed from the conduitare then measured and the measurement is t-aken as an indication of thefuel composition propenties. The conduit may then be prepared foranother test `run such as by cleaning or may be replaced by anotherconduit. lt is important that the conduit be capable of beingcontinuously rotated; rotation of the conduit during use of this deviceprovides a large evaporating surface, symmetrical with regard togravity, and thereby permits use of a shorter conduit than would bepossible without such rotation.

FIGURE l illustrates an embodiment of the device of this invention.

FIGURES II to IV illustrate alternative forms of heating means usablewith the device of this invention.

With reference to FIGURE I of the drawings and with reference to theembodiment illustrated therein, conduit il is provided in chamber l2within best receiving proximity to heating means 13. Conduit 11 iselongated and of such configuration so as to provide substantial lateraland bottom confinement of a fluid engine fuel iiowing from end to endtherethrough. Conduit il is preferably essentially straight to allowproper rotation and free flow of an engine fuel fluid therethroughwithout permitting appreciable amounts of the liuid to col lect at anypoint along the conduit. The conduit is readily removable from chamberl2 and heating means i3 and is interchangeable with other conduits. Forany series of tests of a fuel or fuels to be used for comparisonpurposes, the same basic conguration of conduit i1 must be used. Conduitis constructed of a solid material which is heatable within the range offrom about 100 F. to about 700 F., such as, for example, glass, carbonsteel, stainless steel, other alloy steels, galvanized steel, brass,copper, silver, aluminum, Bakelite, and the like. Where conduit il is atube, glass is a preferred material since it allows visual observationof the deposits as to their position and nature within the tube.Conduits of different materials may be provided and may beinterchangeable for alternating use, e.g., for the purpose ofdetermining the eliects of such dilferent materials on gum deposition.Conduit 11 is rotatably fitted within the chamber of heating means 13with suiiiciently snug fitting to retard its longitudinal gravitationalmovement from chamber l2 but sufficiently loose to permit rotation ofconduit il within chamber 12. Conduit 1l is thereby held in heatableassociation with heating means 13 and is rotatable during use.

Chamber i2 within heating means 13 is an elongated chamber throughheating means 13 and is adapted to receive conduit 11 as hereinabovedescribed. Chamber i2 may be an elongated tube, such as for example ametal tube, in which conduit 11 is snug tted or chamber i2 may simple bea passageway or space provided within heating means 113 such asillustrated in FIGURE I, or may be constructed as a part of heatingmeans 13. Chamber l2 is in any event advantageously provided with meansfor assuring the snug rotatable fit of conduit li therein such as isprovided by the snug packing of insulation i6 around conduit lll at eachend of chamber i2 as illustrated in FIGURE l or as may be provided bynger projections, ribs or rings within chamber l2 at various positionsalong chamber 12, such as for example, at each end of chamber l2.

The heating means may be any means capable of heating conduit il andmaintaining a preselected constant or gradient temperature in conduitlll. The heating means may advantageously be an electrically operatedheating coil controlled at a pre-selected temperature by thermostats inthe wall of conduit li. In the embodiment of FiGURE i, the heating meansincludes a heat exchange jacket I3 surrounding conduit lil and adaptedfor iiow of heat exchange liuid therethrough. The heat exchange iiuid issupplied by boiler 27 and condenser 29. A liquid of constant boilingpoint is charged to boiler 27 and heat is applied by heat source 23which may be gas burner, electrical heating coil, furnace, etc. Theliquid in boiler 27 is vaporized and charged as a heat exchange iluid tojacket 13 through line 27a. The vaporized fluid condenses in jacket 13and/ or reux condenser 29 attached to jacket i3 by means of line 29a andis returned to boiler 27 for revaporization. Conduit 11 is heated byheat exchange with jacket 13.

Examples of constant boiling liquids and temperatures which may beobtained in conduit 1l. with each are as follows: l-2dichlorobenzene(about 350 F.), methyl benzoate (about 390 F.), m-xylene (about 280 to285 F.), 1,2,4-trichlorobenzene (about 415 to 420 F.), and benzoic acidanhydride (about 675 F.).

Jacket i3 is conveniently provided with insulation 16 to conserve heatand protect personnel from burns.

Conduit 1]. is mounted on a slope by mounting means, (not shown) toprovide gravity flow therethrough. The illustrated slope is about 15although it is to be understood that any slope can be used as willprvoide adequate flow. The mounting means may be any such means known tothe art such as, for example, an assembly of clamps and bar stands asare used to position condensers and the like, a sling arrangement, aninclined surface, a supporting biock, etc. The mounting means mayadvantageously be adjustable to provide a number of differing degrees ofslope or inclination in order to regulate gravity iiow rate through andfluid residence time within conduit il. Conduit 11 is thus positioned onan inclination providing an upper inlet end 9 and a lower outlet end ld.inlet end 9 of conduit 11 is provided with fuel inlet line i8 and airinlet line 19. Fuel inlet line 18 is advantageously provided with fuelmeter means such as syringe 22 and air inlet line 19 may advantageouslybe provided with air meter means such as air meter 2l.

Lines 13 and 19 communicate with the interior of conduit it throughchamber 14 in coupling 15 and through upper end 9. Conduit 11 isjournaled to coupling i5 in such a manner as to permit rotation ofconduit 1l without resulting rotation of coupling 15 and lines )i8 and19.

Syringe 22 is a plunger-type syringe adapted for measuring fuel samplesand constitutes the fuel meter means in the embodiment of FIGURE I.Plunger 23 is provided with worm gear receiver 24 which may be a tubehaving projections complementing worm gear 25 for translation ofrotational movement of worm gear 25 into linear movement of receiver 24and plunger 23. Worm gear 25 and receiver 24 comprise a worm gearlinkworks assembly. Drive means 26, for example a constant speedelectric motor, drives worm gear 25 at constant speed resulting inlinear movement of plunger 23 within syringe 22 in a direction toprovide iiow of iiuid from syringe 22 through line i8 at a constantrate.

At outlet end l0 of conduit lll, is outlet coupling 37 containing outletchamber 35. Passing through chamber 35 is a rotatable extension conduit32 which is rotatable with relation to coupling 37. Extension conduit 32has a iiared end 31 into which conduit 11 is friction tted at lower endi9. On extension conduit 32 and within chamber 33 is an opening 3dadapted to permit flow of fluid from extension conduit 32 into chamber35. Vent 36 is provided communicating within chamber 35 for withdrawingfluids from chamber 35. Vent 36 may conveniently be fitted with a vacuumpump (not shown) or the iike to provide better flow of iiuids fromchamber 35.

Drive means, such as constant speed electric motor 33, are provided torotate extension conduit 32 which in turn rotates conduit 11 through thefitted connection of flange 3l at lower end 10. Thus, the drive means isadapted to rotate an elongated conduit assembly formed by conduit il andextension conduit 32. Couplings i5 and 37 are aflixed in stationaryposition with relation to the rotatable conduit assembly.

Drive means 33 and drive means 26 may be controlled such as, forexample, by control means 33, which may be a timer switch, forconcurrently activating and deactivating both drive means, such as bycontrol through leads 39a and 39b and leads 46a and 40h respectively.

As shown in FIGURES II and III respectively, in lieu of boiler 27,jacket 13 and condenser 29 of the embodiment of FIGURE I, anelectrically operated heating coil 50 or a plurality of electricalheating coils may be used in heating conduit i1 in the apparatus ofFIGURE I. Also, in lieu of boiler 27, jacket 13, condenser 29 andinsulation I6, there may be employed a tapered electrical resistanceelement 70 as shown in FIGURE IV. The tapered resistance elementmaintains a temperature gradient along conduit l1 by resistance heating;such a temperature gradient may also be maintained by using coils ofdifferent resistance as coils 6G, 61 and d2 of FIGURE III or by varyingthe coil spacing of coil Si) in FIGURE II. Such means for obtaining atemperature gradient are known to the art.

Supports or holding means (not shown) may be provided to support orposition various elements of the device wherever desired or needed. Forexample, such supports may be provided to hold couplings and 34 and heatexchanger 13 and insulation 16 stationary while rotating the conduit.Supports may also be provided for drive means 26 and 33, timer switch33, air meter 2i', reflux condenser 29, boiler 2'7, heat source 2S, andother elements as desired or needed.

ln operation, with reference to FIGURE I, a sample of fuel to be testedis introduced into syringe 22 and conduit 11 is brought to the desiredtemperature by heating boiler 27 containing a heat exchange fluid. Timerswitch 38 is .then turned on and `dr-ive means 33 and drive means 26 arethereby activated. rI`he fuel sample ilows through line 18 and lapartial vacuum -applied at vent 36 draws air through air meter 2.1 andline 19. The air :meter may be iused -to control the rate of flow of airif desired. Only sufficient amounts of air are necessary to keep theinterior service of conduit 11 swept free of vaporized fuel. Thislamount of air is below that amount necessary to produce a ammabie orexplosive fuel-air mixture.

Fuel from line 18 and air from line 19 are charged through chamber -14in coupling 15 and into conduit 1i which is being rotated at `a`constant speed by drive means 33. The `fuel and air a-re heated inrotating conduit Il and continue owing through conduit 1i into conduitextension 32, Vand chamber 34 and are withdrawn from the Idevice throughvent 36. After the total sample in syringe 22 has been charged throughconduit l1, drive means 26 and 33 are deactivated by timer switch 3S.Timer switch may be provided with automatic means for deactivating drivemeans 26 and 33 after a pre-estimated length of time for the test.

After the test sample 'has been completely run, conduit 11 is removedfrom chamber i2 by disengaging conduit 11 from the friction tit withflange 3i fand from the journal fit with coupling 15. Conduit 11 is thenpulled out endwise from chamber i2.

The deposits in conduit l1, after each test, are mea-sured for depositweight and for deposit movement. The deposit weight may conveniently bedetermined Iby subtrac-ting the weight 'of conduit l1 before the testfrom the weight after the test. With regard to deposit movement, the gumand deposits appear as elongated streamers on the inner surface ofconduit 11. The number of such streams appearing is determined and ameasurement of each streamer is taken. The measure-ment of each streameris the distance from upper end 9 of conduit M to (l) the trailing edgeof, and (2) the furthest point of travel of each measured streamerwithin conduit Ii. It is probable in many tests that no trace ofstreamers d will appear in the upper end of conduit 11, however, themeasurement from the upper end to the funthest point of travel of thestreamer is still taken as a measurement of deposit movement.

During the operation of the device of this invention, with reference tothe actual formation of gum and deposits in streamers within therotating conduit, fuel and air are charged through -t-he heated rotatingtube and deposits form in and/ or separate from the fuel-air mixture.The vfuel-air mixture is maintained in contact with the rotating surfacewithin the conduit and sufficient air is swept through the conduit -tocarry fuel vapors out of the apparatus, e.g. into a vacuum system. Asthe fuel proceeds down the conduit, light ends are distilled off leavingthe heavy ends and gum precursors which are then free to react andfurther distill until, at some point intermediate the upper and lowerends of lthe conduit, viscosity or" the 'liquid ilm formed on the innersurface of the conduit increases to the point that further movement downthe conduit is halted. Thus, at the end of a test, the distance whichthe deposits have moved is measured and Athe deposits ia-re weighed,e.g. after removal from the conduit. Distances of deposit movementcorrespond to distances of the leading edge and/ or trailing edge fromthe conduit inlet. It is important .that the conduit be rotated since,by so rotating, a large evaporating surface, symmetrical with regard togravity, is provided. The large evaporating surface also permitsoveralil shortening of the apparatus and savings therefrom.

Although, in the above descriptions, the heating means provided aconstant temperature within the conduit throughout the test, the heatingmeans may also be one capable of providing la temperature gradient`along the ength of the conduit from one end of the conduit to the otherend of ,the conduit, such as may be attained by using a plurality ofelectrical heating coils or a tapered electrical resistance element.W'here va gradient temperature is provided over the length of theconduit, it may be advantageous that the lower temperatures `be at theinlet of the yconduit and the higher temperatures be at the outlet oftheconduit. Funther, such temperature gradient, when used, may be such asto provide temperatures differing by at 'least about 50 F. along thelength of the conduit. Such gradient temperatures may be used todetermine properties of `fuels under changing 4tempera-ture conditionssuch -as are found in an internal combustion engine. Based on my studyof fuels with this device, I believe that a temperature gradient along:the conduit does not substantially increase accuracy or correlation ofthe device with yactual engine tests, and therefore, I prefer the use ofa constant temperature along the conduit in view of its greater ease ofattainment.

The conduit used for one test may be cleaned with appropriate solventsand may be reused in subsequent tests if desired. v

The device provided herein has become known as the Rotogum tester :andwill, at times, be hereinafter referred to las such, or by like name.The test conducted in the Rotogum tester will ybe referred to as theRotogum test.

Correiation between the Rotogum tester and several laboratory enginetests was studied. The performance with each of 18 fuel-additive blendsin -the Rotogum test was compared with performance in the Lauson EngineInduction System Deposit test (Lauson Engine test) and the UnionInduction System test (Union test.) The test proce dures were :asfoliows:

Lauson Engine Test The Lauson Engine tests were run in accordance with aprocedure described in la paper entitled: Evaluating Gasolines forInduction System Gums by C. C. Moore, I. L. Keller, W. C. Kent and F.Si. Ligget-t, presented before the SAE National Fuels and LubricantsMeeting in Tulsa, Gklahoma, held November 4-5, 1954 (available asPrcsatisfies s print No. 406 from the SAE Special PublicationsDepartment).

Union Test `The Union Induction System tests were run in accordance withthe description in ASTM Special Technical Publication No. 292, Symposiumon Vapor Phase Oxidation of Gasoline, ASTM, Philadelphia, Pennsylvania,June 1957, pp- 21-40, formerly presented at the Second Pacific reaNational Meeting of the above symposium at Los Angeles, California,September 19, 195 6.

Rotogum Test The apparatus used in this test procedure was a resistancefurnace consisting of an insulated heating element positioned yaround acm. length of glass tubing having about a 11A cm. inter-nal diameter.The glass tube constituted the conduit through which each sample :testedwas flowed. The conduit was on an inclined slant at an angie of about30. The glass tube was removable and replaceable with other like glasstubes. A Variac was used to main-tain a :temperature of about 400 F.within the tube and the temps-nature was controlled responsible tothermocouples within the tube. Each sample -tested had a voiume of 1GOml. in the liquid state at room temperature `and each sample was allowedto flow through the glass tube at a sample injection rate of about 2.5nil. per minute. The glass tube was rotated at a constant speed of about72 11pm. The tair flow rate into the glass tube was controlled toprovide a very rich `fuel-to-air mixture by providing less lthanstoichiometric amounts of `ai-r in the glass [tube relative to fuel. Theflow of air was, however, fully suilicient to carry vapors from thetube. The tube was removed `after each sample and the total weight ofdeposits was determined. The length of movement of streamers from theinlet and the numbers of streamers were also determined.

The above three :test procedures lwere run on leaded gasolinecompositions (3 cc. of comercial tetraethyllead fluid) containingvarious addition agents. Eighteen different fuels were used inpreliminary tests to determine the correlation of the Rotogum test withan engine test, i.e. .the Lauson Engine test.

Correlation between the Rotogum and the Lauson Engine tests was studiedwith regard to the performance of the above-mentioned 18 fuel-additiveblends `tested by each procedure. The degree of correlation between thetest units was expressed in terms of the Spearman Rank CorrelationCofiicient. This coeicient is expressed as rho in the following formula:

wherein d is the numerical difference in rank (the quality sequence)between Lauson `and Rotogum test results of the same fuel and n is thetotal number of fuels which were compared in the ltwo units. Had theperformance or quality sequence of the 18 fuels, as determined in the-Rotogum test, been identical to that from the Lauson test, there wouldbe perfect correlation and rho would be equal to unity. If there were nocorrelation at all, then rho would equal zero.

Correlation of deposit weight was .also studied by comparing weight ofthe deposits resulting yin each test.

Rotogum results in correlation with Lauson engine resuits may also berepresented in terms of deposit moveiment. The deposit movement (DM)term is expressed as follows:

l2oo-E XtXill is the distance of each streamer leading edge from theinlet.

Rotogum results may also be expressed in terms of an integratedexpression, the Rotogum rating (RR), as follows:

Rotogum criteria: p Deposit weight 0.81 Deposit movement 0.79 Rating0.85

The 4above reported rho values show that there is a significantcorrelation between the Rotogum and Lauson tests. Further, theinteraction of deposit weight and deposit movement terms, as expressedby the Rotogum rating, is more closely related to engine performancethan either deposit weight or deposit movement terms individually. Byway of comparison of correlation with the Lauson test, the UnionInduction System Apparatus used in the Union test, gave a rho value of0.72 in tests of the same 18 fuels.

Limited full-scale multi-cylinder engine laboratory tests also haveshown good agreement with the Rotogum tester. Additives which improveperformance in the Rotogurn test also reduced induction system depositsin Chevrolet 6 and Oldsmobile tl-8 engines. 4It has also been observedthat certain additives which increase deposit movement in the Rotogumapparatus also function as carburetor detergents in tests conducted witha Pontiac V-8 engine.

Precision of the Rotogum device, in terms of weight deposit, has alsobeen found to be good. Standard deviations, expressed as percents of themean of from 8 to l0 tests using the same fuel, were as follows:

Test: Standard deviation, percent Lauson engine 138 Union inductionsystem l20 Rotogum x15 The Rotogum device gives precise data in the sameor a lesser amount of time than either of the other two tests consideredabove, even though the Rotogum tests are run in duplicate for improvedcalculated precision.

it is evident from the above that l have provided a new device andtesting procedure for determining deposit propenties of engine fuelcompositions and particularly such properties as relate to depositweight and deposit movement in the fuel induction system of an internalcombustion engine. The results obtained are correlated with resultsobtained in an actual operating internal combustion engine.

I claim:

l. An engine fuel test device for indicating gum and deposit formingproperties of an engine fuel which device comprises a jacket heatingmeans having an elongated chamber, a heatable and rotatable elongatedconduit within said chamber and `longitudinally and rotatably moveablewithin and removable from said chamber, stationary inlet means at afirst end of said conduit for charging fluid engine fuel andoxygen-containing gas to said conduit, said stationary inlet meanshaving inlet coupling means attached to said rotatable conduit, meansfor metering the flow of engine fuel and oxygen-containing gas to saidconduit, said means including a plunger driven means for metering saidengine fuel, stationary outlet means at a second end of said conduit,said stationary outlet means having outlet coupling means attached tosaid rotatable conduit, said conduit being adapted for rotation on anaxis extending between said inlet means and said outlet means andsubstantially connecting said inlet means and said outlet means, meanspositioning said conduit on a slope whereby longitudinal gravity flow isprovided from said inlet means to said outlet means, an inner surfacewithin said conduit and capable of collecting gums and deposits,temperature control means for controlling the temperature of said innersurface at a preselected temperature within the range of from about 100F. to about 700 F., motor driven means for rotating said conduit on saidaxis at a substantially constan-t speed, time actuated means forcontrolling said motor driven means for rotating whereby said means forrotating is capable of activation and deactivation, and means permittingthe removal of said conduit `from said chamber `whereby gum and depositson said inner surface may be measured as an indication of gum `anddeposit properties correlated with the gum and deposit weight andmovement tendencies `of said engine fuel in the fuel-induction system ofan operating internai combustion engine.

2, An engine fuel test device for ascertain-ing the mobility and Weightof gum land deposits through the fuelinduction system of an internalcombustion engine Where gum and deposits are formed in the fuel, whichdevice comprises a heating jacket vadapted for ow of heating uidtherethrough, a rotatable heatable elongated cylindrical conduitremovably positioned within said jacket in heat receiving proximity tosaid jacket, means positioning said jacket containing said conduit on aninclined slant whereby the two ends of said conduit are definable as anupper end and a lower end with relation to each other,

said inclined slant being sufcient to provide gravity ilow of 'luid fuelthrough said conduit from said upper end to said lower end, at saidupper end an inlet coupling containing an inlet chamber communicatingWithin said upper end of said conduit, said upper end being journaled insaid inlet coupling, an air conduit communicating with said inletchamber for carrying air to said inlet chamber, a plunger-type syringe`adapted to charge fuel to said inlet chamber, a constant speed irstelectric motor, Worm gear link-works positioned between said iirst motorand the plunger of said syringe and adapted to convert the rotarymovement of said motor into linear movement of said plunger within saidsy1inge, at the lower end of said conduit, a removably connectedrotatable cylindrical tubular extension of said conduit, said extensionbeing friction connected to said lower end and rotatably protrudingthrough an outlet coupling having an outlet chamber, means for uidcommunication between said outlet chamber and the interior of saidextension, means for withdrawing lluid from said outlet chamber, aconstant speed second electric motor adapted to rotate said extensionand said conduit, and timer switch means for controlling said rst andsecond motors and providing concurrent activation and deactivation ofsaid motors.

References Cited in the tile of this patent UNITED STATES PATENTS

2. AN ENGINE FUEL TEST DEVICE FOR ASCERTAINING THE MOBILITY AND WEIGHTOF GUM AND DEPOSITS THROUGH THE FUELINDUCTION SYSTEM OF AN INTERNALCOMBUSTION ENGINE WHERE GUM AND DEPOSITS ARE FORMED IN THE FUEL, WHICHDEVICE COMPRISES A HEATING JACKET ADAPTED FOR FLOW OF HEATING FLUIDTHERETHROUGH, A ROTATABLE HEATABLE ELONGATED CYLINDRICAL CONDUITREMOVABLY POSITIONED WITHIN SAID JACKET IN HEAT RECEIVING PROXIMITY TOSAID JACKET, MEANS POSITIONING SAID JACKET CONTAINING SAID CONDUIT AREDEFINABLE AS WHEREBY THE TWO ENDS OF SAID CONDUIT ARE DEFINABLE AS ANUPPER END AND A LOWER END WITH RELATION TO EACH OTHER, SAID INCLINEDSLANT BEING SUFFICIENT TO PROVIDE GRAVITY FLOW OF FLUID FUEL THROUGHSAID CONDUIT FROM SAID UPPER END TO SAID LOWER END, AT SAID UPPER END ANINLET COUPLING CONTAINING AN INLET CHAMBER COMMUNICATING WITHIN SAIDUPPER END OF SAID CONDUIT, SAID UPPER END BEING JOURNALED IN SAID INLETCOUPLING, AN AIR CONDUIT COMMUNICATING WITH SAID INLET CHAMBER FORCARRYING AIR TO SAID INLET CHAMBER, A PLUNGER-TYPE SYRINGE ADAPTED TOCHARGE FUEL TO SAID INLET CHAMBER, A CONSTANT SPEED FIRST ELECTRICMOTOR, WORM GEAR LINK-WORKS POSITIONED BETWEEN SAID FIRST MOTOR AND THEPLUNGER OF SAID SYRINGE AND ADAPTED TO CONVERT THE ROTARY MOVEMENT OFSAID MOTOR INTO LINEAR MOVEMENT OF SAID PLUNGER WITHIN SAID SYRINGE, ATTHE LOWER END OF SAID CONDUIT, A REMOVABLY CONNECTED ROTATABLECYLINDRICAL TUBULAR EXTENSION OF SAID CONDUIT, SAID EXTENSION BEINGFRICTION CONNECTED TO SAID LOWER END AND ROTATABLY PROTRUDING THROUGH ANOUTLET COUPLING HAVING AN OUTLET CHAMBER, MEANS FOR FLUID COMMUNICATIONBETWEEN SAID OUTLET CHAMBER AND THE INTERIOR OF SAID EXTENSION, MEANSFOR WITHDRAWING FLUID FROM SAID OUTLET CHAMBER, A CONSTANT SPEED SECONDELECTRIC MOTOR ADAPTED TO ROTATE SAID EXTENSION AND SAID CONDUIT, ANDTIMER SWITCH MEANS FOR CONTROLLING SAID FIRST AND SECOND MOTORS ANDPROVIDING CONCURRENT ACTIVATION AND DEACTIVATION OF SAID MOTORS.